An insulating glazing, also known as multiple glazing, comprises several glazings separated by a cavity filled with gas (argon, krypton, air, and the like), optionally under reduced pressure. It can be a double glazing if it comprises only a single gas-filled cavity separating two glazings. It can be a triple glazing if it comprises two gas-filled cavities and three glazings, each gas-filled cavity separating two of the glazings.
A glass substrate comprises a single sheet of mineral glass, if appropriate covered with one or more thin layers of the following types, antireflection, solar-protection, abrasion-resistant, and the like. A glass substrate of an insulating glazing can form part of a laminated glazing. An insulating glazing can be composed exclusively of laminated glazings separated by a gas-filled cavity. In all cases, an insulating glazing comprises at least one gas-filled cavity separating two glass substrates, it being possible for each of these glass substrates, if appropriate, to form part of a laminated glazing.
A laminated glazing comprises several glass substrates separated by an interlayer made of polymer material. The preparation of flat insulating or laminated glazings is well mastered. The preparation of bent laminated glazings is much more problematic and increasingly problematic as the curvatures to be conferred increase. If the curvatures are high, the hot bending beforehand of the glass sheets while the glass is soft (generally at greater than 500° C.) may be necessary. If the curvatures of a glazing are not very great, it is possible to envisage cold bending it after the end of the manufacture thereof. The expression “cold bending” generally means at less than 200° C., at which temperature the glass is not soft. In the context of the present patent application, “cold bending” means “at less than 200° C.”.
WO98/01649 teaches the cold bending of a laminated glazing.
EP 282 468 teaches the bending between 80 and 140° C. of a laminated glazing comprising a dip-coated glass substrate. Heating between 80 and 140° C. serves to soften the interlayer PVB of the laminated glazing. However, the bending of a laminated glazing above 80° C. results in an unacceptable aging of the interlayer made of polymer material, which is reflected by the formation of fine bubbles but ones visible to the naked eye, and furthermore that it is advantageously possible to carry out the cold bending between 30 and 80° C., to reduce the loads necessary for the bending and also the shear stresses between the interlayer made of polymer material and the glass substrates and thus reduce the risks of delamination.
FR 2 676 049 and DE102008031770 teach the assembling of a glazing laminated by a PVB, the glass sheets being curved during the assembling operation. It is thus the PVB which maintains the curving of the laminated glazing.
DE19519504 teaches the bending of a laminated glazing at 130° C.
WO2008107612 teaches an insulating glazing incorporating a pane bent before assembling the insulating glazing.